<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>test-操作元素</title>
</head>

<body>
    <!-- 
    1.世纪佳缘用户名显示隐藏内容
    2.京东关闭广告（直接隐藏即可)
    3.新浪下拉菜单（微博即可)
    4.开关灯案例(见素材)
     -->
</body>

</html>